Snap-action switch for vibrating a resonant reed



Jan. 30, 1968 F. UMPLEBY 3,366,766

SNAP-ACTION SWITCH FOR IIBRATING A RESONANT REED Filed Jan. 7, 1965 2 Sheets-Sheet 2 v m4 IVE MJFIG. 7

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, ATTORNEY5 MPLEBY' 3,366,766 SNAP-ACTION SWITCH FOR VIBRATHJG A RESONANT REED Kenneth F. Umpleby, Ann Arbor, Mich, assignor to Berry Industries, Inc., Birmingham, Mich, a corporation of Mlichigan Filed Jan. 7, 1965, Ser. No. 424,095 3 Claims. (Cl. 200-181) This invention relates generally to a snap-action switch and more particularly to a switch which is capable of making and breaking an electrical connection while simultaneously initiating vibration of a resonant reed.

The objects of this invention are to provide a snapaction switch that is constructed simply and economically; that is fast acting and makes rapid positive contact; that provides a mechanical impulse useful in vibrating a resonant reed without adversely affecting electrical parameters of the reeds; and that provides a minimum mechanical impulse and a minimum switching cycle duration sub stantially independent of the operator after a minimum force has been exerted on the switch.

In the drawings:

FIG. 1 is an electrical circuit diagram of a remote control transmitter which is amplitude modulated in accordance with capacitive variations provided by a reed assembly and which includes a snap-action switch constructed in accordance with one aspect of the present invention to substantially simultaneously energize the transmitter and vibrate reeds in the reed assembly.

FIG. 2 is a top view of a transmitted case with the cover removed to illustrate the construction and placement of transmitter parts including the snap-action switch.

FIG. 3 is a view taken on line 33 of P16. 2 to further illustrate the reed assembly and the snap-action switch with the switch being shown in an open position.

FIG. 4 is a view of the snap-action switch in an operated or closed position.

FIG. 5 is a side view of the reed assembly taken on line 55 of FIG. 2.

FIG. 6 is an exploded view of the snap-action switch constructed in accordance with the present invention.

FIG. 7 is a fragmentary vertical section illustrating a magnetic keeper swedged on a bracket in the switch.

FIG. 1 shows a portable transmitter 10 in which a carrier signal from a source 12 is amplitude modulated by an amplifier 14 in accordance with capacitive variations in a vibrating reed assembly 16. Transmitter 10 is particularly suited for a garage door operator controlled remotely. Assembly 16 is connected in a secondary circuit 18 which in turn is coupled to a tank circuit 20 in amplifier 14. A switch 22 constructed in accordance with the present invention is arranged to connect amplifier 14 to a battery 24 and simultaneously create a shock impulse which is transmitted to reed assembly 16. Secondary circuit 18 includes a secondary winding 26 coupled magnetically to tank 20 and connected in series with a high-Q coil 28, a trimmer capacitor 30, and reed assembly 16.

Transmitter 10 also comprises a two-piece plastic case 34 (FIGS. 2, 3, and 4) formed with a base 36 and a cover 38 (FIG. 3). A circuit board 40 is fioatably mounted on base 36 interiorly of case 34 by four screws 42 and a sponge rubber pad 44. Screws 42 are threaded into base 36 to limit upward travel of board 40 as viewed in FIG. 3. Pad 44 is compressed between board 48 and atent base 36 to yieldably urge the board away from the base.

Reed assembly 16 comprises a heavy brass base 50 which supports a flat fiberglass board 52 in spaced relation to board 40. Board 52 projects laterally outwardly of base 50 and has a flat metal plate 54 mounted thereon laterally outwardly of base 50 adjacent the free end of board 52. Resting on and disposed above board 52 is a flat spacer 56 which in turn supports a reed subassembly 58. Subassembly 58 comprises a U-shaped reed clamp 60 (FIG. 5) and a pair of flexible reeds 64, 66, one end of each reed being clamped between the legs of clamp 60. Clamp 60 is made of brass and emersed in molten solder with the ends of reeds 64, 66 disposed therein to form a unitary assembly. Reeds 64, 66 project laterally outwardly from clamp 60 so as to be spaced above and overlie an upper face 68 of plate 54. Resting on reed subassembly 58 is a heavy brass block 70. Base 50 and block 70 have a relatively large mass to improve the vibration characteristics of reeds 64, 66. Board 40, base 50, board 52, spacer 56, reed subassembly 58, and block 70 are all perforated to accommodate a screw 72 therethrough. A nut '74 is threaded on the lower end of screw 72 below board 40 to clamp the parts together and to board 40. Nut 74 may be soldered to screw 72 together with a lead 76 (FIGS. 1 and 5) for electrically connecting reeds 64, 66 to capacitor 30. Plate 54 is electrically connected to winding 26 by a lead 78 (FIGS. 1 and 5).

Reeds 64, 66 are substantially identical except in length so that they have different resonant vibration frequencies. Reeds 64, 66, together with plate 54, form a capacitance which varies in accordance with the vibration frequency of the reeds when the reeds vibrate. Reeds 64, 66 are formed of commercially available alloy steels that mini mize the effect of ambient temperature variations and have desirable elasticity characteristics. The free end, left end as viewed in FIGS. 2 and 5, of each reed 64, 66 extends laterally outwardly beyond plate 54 so that regardless of the length of the reed, a substantially equal reed area will overlie plate 54. With this construction, the capacitance of reed assembly 16 will be substantially the same regardless of the length of the reeds. Thus, different reeds and pairs of reeds can be used interchangeably without substantially modifying the other circuit components shown in FIG. 1.

Switch 22 (FIGS. 3, 4, and 6) comprises a U-shaped bracket having vertical legs 92, 94 each of which is fashioned with a lug 96, 98. Lugs 96, 98 project through a pair of apertures 100, 102 (FIG. 6) in board 40 and are bent laterally outwardly to fasten bracket 90 on board 40. Bracket 90 also has a flat bight portion 104 fashioned with a central aperture 106 therethrough. An annular collar 108 having an axial flange 110 is fastened on bracket 90 beneath bight 104 by inserting flange 110 through aperture 106 and swedging flange 110 over the top of bight 104 (FIG. 7). Collar 108 serves as a guide for a. vertically slidable shaft 112. A metal washer 114 is fastened directly on the upper end of shaft 112. A push button 116 is also fastened on shaft 112 directly above washer 1.14. Button 116 projects upwardly through a suitable aperture in cover 38 and has a radial flange 117 that bottoms on cover 38 (FIG. 3). A spring leaf 118 is fastened on leg 92 and has an upper free end 120 bent laterally over bight 104 to engage washer 114. Washer 114, shaft 112, and leaf 118 are made of metal to form a conducting path through switch 22.

3 Shaft 112 is fashioned with a stepped shoulder 122 and an ensmalled lower extension 124. A magnet 126 having a central aperture 128 is slidably disposed on extension 124. Shoulder 122 abuts magnet 126 around the periphery of aperture 128 so that shaft 112 carries magnet 126 downwardly when button 116 is pressed. Collar 108 is formed of magnetic material to serve as a keeper for magnet 126 and releasably retain magnet 126 in the position illustrated in FIG. 3. Extension 124 is vertically in line with an aperture 130 in board 40. A contact arm 132 is fastened on the bottom of board 40 and has a free end 134 disposed beneath aperture 130 and spaced from the bottom of extension 124. Arm 132 is engaged by extension 124 when shaft 112 moves downwardly as viewed in FIG. 4. A lead 136 (FIGS. 1, 3, and 4) is electrically connected between arm 132 and battery 24. A lead 138 is electrically connected between lug 96 and the transistor in amplifier 14.

When button 116 is pushed downwardly as viewed in FIG. 3, the magnetic coupling between magnet 126 and collar 108 is broken with a snapping action so that magnet 126 strikes board 40 with sufficient impact to establish a mechanical impulse or shock which is transmitted through board 40 to reed assembly 16 to initiate vibration of reeds 64, 66. Simultaneously, extension 124 contacts arm 132 to connect amplifier 14 to battery 24 via lead 136, arm 132, shaft 112, washer 114, leaf 118, bracket 90, and lead 138. When button 116 is released, magnet 126 snaps back into engagement with collar 108, disengaging extension 124 from arm 132 when arm 132 bottoms against board 40. As reeds 64, 66 vibrate, the capacitance of reed assembly 16 in the secondary circuit 18 varies in accordance with the reed vibration frequency.

Although the use of capacitive variations in reed assembly 16 does not form a necessary part of the present invention, by way of further illustration, the capacitive variations amplitude modulate the carrier signal from source 12. In general, tank circuit 20 is tuned to parallel resonance at the carrier frequency of source 12. Source 12 should provide a stable carrier frequency as by use of a crystal-controlled oscillator. Secondary circuit 18 is tuned reactively just off series resonance in a direction such that when reed 64, 66 vibrate, secondary circuit 18 is tuned toward and away from series resonance for the carrier frequency of source 12 in accordance with the reed vibration frequencies. Thus, tank circuit 20 and secondary circuit 18, taken together, are tuned reactively for the carrier frequency of sources 12 in a direction such that when reeds 64, 66 vibrate to tune the secondary circuit 18 toward and away from series resonance, the tank circuit 20 is tuned toward and away from parallel resonance thereby modulating current in tank circuit 20 and hence power radiated therefrom in accordance with capacitive variations in reed assembly 16.

Switch 22 is also constructed simply and economically to provide an effective means for initiating vibration of reeds 64, 66 and minimizing accidental actuation of the transmitter. Since switch 22 is remote from reed assembly 16, movement of switch 22 does not adversely affect the capacitance between reeds 64, 66 and plate 54 as might occur if the reeds were plucked directly. Switch 22 further reduces the cost of the transmitter by also serving as an on-oif switch for power to amplifier 14. Once switch 22 is pressed, only one modulated carrier pulse of short duration is transmitted. The duration of the modulated carrier depends on the damped vibration of the reeds and cannot be extended by keeping the button depressed. On the other hand, once the operator applies sufiicient force to uncouple magnet 126, the momenturn of magnet 126 assures that switch 22 will always complete its cycle by first engaging extension 124 with arm 132, striking board 411, and then disengaging extension 124 from arm 132. Stated differently, it is practically impossible to uncouple magnet 126 from collar 108 without also striking board 40 with magnet 126. Magnet 126 will always strike board 40 with at least a minimum impact sulficient to effectively vibrate reeds 64, 66 while amplifier 14 is on. Extension 124 engages arm 132 during most of the upward and downward travel of extension 124 so that power is supplied to the amplifier 14 just prior to and during vibration of reeds 64, 66. Thus, a minimum duration for the switch cycle and a minimum duration for the modulated carrier is guaranteed. On the other hand, amplifier 14 is connected to battery 24 only while switch 22 is operated. Thus, switch 22 minimizes drain on battery 24 which is extremely desirable in portable transmitters.

The operator has no doubt as to whether button 24 was properly depressed. There is a positive snap-action or give at button 116 when magnet 126 uncouples from collar 108. Also, there is an audible click when magnet 126 strikes board 40 on the downstroke and when the magnet 126 strikes collar 108 on the upstroke. Electrical contact is made rapidly and broken rapidly by the snapaction of the switch.

What is claimed is:

1. An aparatus comprising electrical circuit means having a resiliently flexible reed for providing a signal variation in said circuit means when said reed vibrates, said apparatus further comprising a circuit board, a reed support, said reed being operatively mounted on said reed support and said reed support being operatively mounted on said circuit board so that said reed vibrates in response to a mechanical impulse transmitted to said reed through said board and said support and mechanical switch means operatively mounted on said board remote from said reed support for creating said mechanical impulse comprising a bracket mounted on said board, a plunger slidably mounted on said bracket for movement relative to said board, and magnetic coupling means for releasably retaining said plunger on said bracket in a first position relative to said board, said plunger having a portion thereof spaced from said board when said plunger is in said first position with said plunger portion disposed to engage said board when said plunger is moved from said first position to a second position and said magnetic coupling means including a closed magnetic path which is broken with a snap action as said plunger is moved from said first position toward said second position so that said plunger portion strikes said board with sufiicient impact to create said impulse.

2. The apparatus set forth in claim 1 wherein said circuit means further comprises a capacitor plate, said reed and said plate are electrically coupled in said circuit means to provide capacitive reactance in said circuit means, and said capacitor plate is operatively mounted on said support and disposed relative to said reed in spaced relation therewith so that the space between said reed and the plate varies when said reed vibrates to cause capacitive reactance variations in said circuit means.

3. An apparatus comprising an electrical circuit, a flexible reed operatively connected in said circuit to provide a signal variation in said circuit when said reed vibrates, a support, said reed being operatively mounted at one position on said support to vibrate in response to a mechanical impulse at said support, manually operated mechanical switch means for striking said support without direct engagement between said switch means and said reed to create said mechanical impulse in said supvibration, and wherein said circuit further comprises a.

power supply for energizing said circuit, said mechanical switch means comprises a pair of electrical contacts connected in said circuit to connect and disconnect said power 5 supply, and said mechanical switch means further comprises a plunger moveable to strike said support, one of said contacts being carried on said plunger to operate said contacts in response to movement of said plunger.

References Cited UNITED STATES PATENTS Hester 20061.01 Laporte 20061.01 X Zozulin et a1. 20067 Combs 20067 Umpleby et al 200-61.01

BERNARD A. GILHEANY, Primary Examiner.

H. A. LEWITTER, Assistant Examiner. 

1. AN APPARATUS COMPRISING ELECTRICAL CIRCUIT MEANS HAVING A RESILIENTLY FLEXIBLE REED FOR PROVIDING A SIGNAL VIRATION IN SAID CIRCUIT MEANS WHEN SAID REED VIBRATES, SAID APPARATUS FURTHER COMPRISING A CIRCUIT BOARD, A REED SUPPORT, SAID REED BEING OPERATIVELY MOUNTED ON SAID REED SUPPORT AND SAID REED SUPPORT BEING OPERATIVELY MOUNTED ON SAID CIRCUIT BOARD SO THAT SAID REED VIBRATES IN RESPONSE TO A MECHANICAL IMPULSE TRANSMITTED TO SAID REED THROUGH SAID BOARD AND SAID SUPPORT AND MECHANICAL SWTICH MEANS OPERATIVELY MOUNTED ON SAID BOARD REMOTE FROM SAID REED SUPPORT FOR CREATING SAID MECHANICAL IMPULSE COMPRISING A BRACKET MOUNTED ON SAID BOARD, A PLUNGE SLIDABLY MOUNTED ON SAID BRACKET FOR MOVEMENT RELATIVE TO SAID BOARD, AND MAGNETIC COUPLING MEANS FOR RELEASABLY RETAINING SAID PLUNGER ON SAID BRACKET IN A FIRST POSITION RELATIVE TO SAID BOARD, SAID PLUNGER HAVING A POR- 